Answers for "popup dialog in flutter"

flutter how to pop a dialog box from another component

BuildContext dialogContext;
  showDialog(
    context: context,
    barrierDismissible: false,
    builder: (BuildContext context) {
      dialogContext = context;
      return Dialog(
        child: new Row(
          mainAxisSize: MainAxisSize.min,
          children: [
            new CircularProgressIndicator(),
            new Text("Loading"),
          ],
        ),
      );
    },
  );

  await _longOperation();
  Navigator.pop(dialogContext);

show dialog box on pressed flutter

@override
Widget build(BuildContext context) {
  return Scaffold(
    appBar: AppBar(title: Text("Testing")),
    body: Center(
      child: RaisedButton(
        child: Text("Show dialog"),
        onPressed: () {
          showDialog(
            context: context,
            builder: (context) {
              return Dialog(
                shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(40)),
                elevation: 16,
                child: Container(
                  height: 400.0,
                  width: 360.0,
                  child: ListView(
                    children: <Widget>[
                      SizedBox(height: 20),
                      Center(
                        child: Text(
                          "Leaderboard",
                          style: TextStyle(fontSize: 24, color: Colors.blue, fontWeight: FontWeight.bold),
                        ),
                      ),
                      SizedBox(height: 20),
                      _buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 1", score: 1000),
                      _buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 2", score: 2000),
                      _buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 3", score: 3000),
                      _buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 4", score: 4000),
                      _buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 5", score: 5000),
                      _buildName(imageAsset: 'assets/chocolate.jpg', name: "Name 6", score: 6000),
                    ],
                  ),
                ),
              );
            },
          );
        },
      ),
    ),
  );
}

Widget _buildName({String imageAsset, String name, double score}) {
  return Padding(
    padding: const EdgeInsets.symmetric(horizontal: 20.0),
    child: Column(
      children: <Widget>[
        SizedBox(height: 12),
        Container(height: 2, color: Colors.redAccent),
        SizedBox(height: 12),
        Row(
          children: <Widget>[
            CircleAvatar(
              backgroundImage: AssetImage(imageAsset),
              radius: 30,
            ),
            SizedBox(width: 12),
            Text(name),
            Spacer(),
            Container(
              padding: EdgeInsets.symmetric(vertical: 8, horizontal: 20),
              child: Text("${score}"),
              decoration: BoxDecoration(
                color: Colors.yellow[900],
                borderRadius: BorderRadius.circular(20),
              ),
            ),
          ],
        ),
      ],
    ),
  );
}

flutter show dialog on start

import 'dart:async';
  import 'package:flutter/material.dart';

  void main() {
    runApp(new MyApp());
  }

  class MyApp extends StatelessWidget {
    @override
    Widget build(BuildContext context) {
      return MaterialApp(
          title: 'Trial',
          home: Scaffold(
              appBar: AppBar(title: Text('List scroll')), body: new MyHome()));
    }
  }

  class MyHome extends StatelessWidget { // Wrapper Widget
    @override
    Widget build(BuildContext context) {
      Future.delayed(Duration.zero, () => showAlert(context));
      return Container(
        child: Text("Hello world"),
      );
    }

    void showAlert(BuildContext context) {
      showDialog(
          context: context,
          builder: (context) => AlertDialog(
                content: Text("hi"),
              ));
    }
  }

popup flutter

import 'package:flutter/material.dart';

void main() {
  runApp(new MaterialApp(home: new MyApp()));
}

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  final _formKey = GlobalKey<FormState>();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Flutter"),
      ),
      body: Center(
        child: RaisedButton(
          onPressed: () {
            showDialog(
                context: context,
                builder: (BuildContext context) {
                  return AlertDialog(
                    content: Stack(
                      overflow: Overflow.visible,
                      children: <Widget>[
                        Positioned(
                          right: -40.0,
                          top: -40.0,
                          child: InkResponse(
                            onTap: () {
                              Navigator.of(context).pop();
                            },
                            child: CircleAvatar(
                              child: Icon(Icons.close),
                              backgroundColor: Colors.red,
                            ),
                          ),
                        ),
                        Form(
                          key: _formKey,
                          child: Column(
                            mainAxisSize: MainAxisSize.min,
                            children: <Widget>[
                              Padding(
                                padding: EdgeInsets.all(8.0),
                                child: TextFormField(),
                              ),
                              Padding(
                                padding: EdgeInsets.all(8.0),
                                child: TextFormField(),
                              ),
                              Padding(
                                padding: const EdgeInsets.all(8.0),
                                child: RaisedButton(
                                  child: Text("Submitß"),
                                  onPressed: () {
                                    if (_formKey.currentState.validate()) {
                                      _formKey.currentState.save();
                                    }
                                  },
                                ),
                              )
                            ],
                          ),
                        ),
                      ],
                    ),
                  );
                });
          },
          child: Text("Open Popup"),
        ),
      ),
    );
  }
}